Aircraft reference database • Mode-S / ICAO24

ICAO24 Aircraft Lookup.

Enter a six-character Mode-S hexadecimal address to identify the aircraft registration and, where preserved, its aircraft type, manufacturer, construction number and airline/operator.

What is an ICAO24 address?

From a hex code to the aircraft behind it.

An ICAO24 address is a 24-bit aircraft address normally written as six hexadecimal characters, for example 47161A. It is widely encountered in Mode-S and ADS-B receiver logs, flight-tracking software, SBS/BaseStation data and historical aircraft databases.

This lookup uses the restored ACARSd and libhomeradar reference data. The recovered 2008 snapshot alone contains almost 19,000 historical ICAO24-to-registration mappings, including aircraft that have since been retired, deregistered or disappeared from modern fleet lists.

Useful search terms

Mode-S hex code • ICAO24 address • aircraft registration • tail number • aircraft type • construction number • airline/operator

A Mode-S address or registration may have changed during an aircraft's lifetime, so old mappings are preserved rather than silently overwritten.

Have an aircraft registration instead? Open the Registration Lookup →

Reset

AIRCRAFT RECORDS

Aircraft

9H-QAG

4D21EF
Registration
9H-QAG
ICAO24 / Mode-S
4D21EF
Manufacturer
Boeing
Aircraft type
737-800
Engine types
CFMI CFM56-7B26
Year built
—
ICAO type
B738
Construction number
44815 / 6774
Operator
Ryanair Ltd. - Ireland
Operator codes
RYR
Aircraft country
MaltaDerived from the ICAO24 address allocation.

Loading aircraft photograph…

View all contacts with this aircraft recorded in the database →

ICAO24 result

4D21EF — 1 match

LAST 5 CONTACTS WITH THIS AIRCRAFT

Date / timeRegistrationFlightICAO24Label
2026-11-05 10:00:51 9H-QAG FR04AU 4D21EF **
2026-11-05 08:18:45 9H-QAG FR44HV 4D21EF **
2026-11-04 14:19:18 9H-QAG RYR4AU 4D21EF ADSB
2026-11-04 14:17:59 9H-QAG RYR4AU 4D21EF ADSB
2026-11-04 14:17:45 9H-QAG RYR4AU 4D21EF ADSB
About this database

An actively maintained aircraft reference database.

The ACARSd aircraft database is continuously maintained to keep its records up to date. New aircraft and ICAO24 mappings are added, existing entries are corrected and updated, and outdated entries are removed as needed.

Restored ACARSd data and historical Mode-S/ICAO24 mappings from the libhomeradar archive form part of its foundation.